1. Field of the Invention
The present invention relates to a door lock, and more particularly, to a door lock which generates alarm when an unauthorized entering happens regardless of opening of a door.
2. Description of the Related Art
A locking device consisting of a lock and a key has long been used. A locking device using a password, in which a predetermined series of numbers are set by turning a dial for unlocking, has widely been used.
As an unauthorized unlocking method with respect to these locking devices are becoming known, various locking devices preventing such an unauthorized unlocking has been suggested. For example, a computer key, a finger print recognizing system, and a card key have been introduced. The locking devices are not only used for a personal saving and in a variety of places such as offices and banks, but also for a locking device of an entrance door in private houses.
These locking devices are superior in performance because only a person who knows a password or has a card key can unlock the door. However, the locking devices are useless when an intruder breaks a door where the locking device is installed.